Department of Aquaculture and Fisheries Management
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Item Influences of land use/cover on water quality in the upper and middle reaches of River Njoro, Kenya(Blackwell Publishing Asia Pty Ltd, 2007) Muchiri, Mucai; Shivoga, William A.; Kibichi, Samuel; Odanga, Jethro; Miller, Scott N.; Baldyga, Tracy J.; Enanga, Eric M.; Gichaba, Maina C.Item Spatial and seasonal variations in phytoplankton community structure in alkaline–saline Lake Nakuru, Kenya(Blackwell Publishing Asia Pty Ltd, 2009) Mucai, Muchiri; Okoth, Oyoo Elijah; Shivoga, Wiliam A.; Miller, Scott N.; Rasowo, Joseph; Ngugi, Charles ChegeItem Exotic introductions to the fishery of Lake Victoria: What are the management options?(2005) Muchiri, M.; Knaap, M. van; Cowx, I. G.; Waithaka, E.; Njiru, M.Item Shifts in the food of Nile tilapia, Oreochromis niloticus (L.) in Lake Victoria, Kenya(African Journal of Ecology, 2004) Muchiri, M.; Cowx, I. G.; Okeyo-Owuor, J. B.; Njiru, M.Item Macroinvertebrate assemblages along a land-use gradient in the upper River Njoro watershed of Lake Nakuru drainage basin, Kenya(Blackwell Publishing Asia Pty Ltd, 2007) Muchiri, Mucai; Miller, Scott N.; Shivoga, William A.; Kibichii, SamuelItem Organochlorine and organophosphorus pesticide concentrations in water, sediment, and selected organisms in Lake Naivasha (Kenya)(Kluwer Academic Publishers, 2002) Muchiri, Muchai; Gitahi, S. M.; Harper, D. M.; Tole, M. P.; Ng’ang’a, R. N.Item Changes in population characteristics and diet of Nile tilapia Oreochromis niloticus (L.) from Nyanza Gulf of Lake Victoria, Kenya: what are the management options?(Taylor &Francis, 2007-11-26) Muchiri, Muchai; Njiru, M.; Okeyo-Owuor, J. B.; Cowx, I. G.; Knaap, M. van derItem Remote Sensing Applications for Sustainable Aquaculture in Africa(IEEE, 2007) Quansah, Joseph, E.; Rochon, Gilbert, L.; Quagrainie, Kwamena, K.; Amisah, Steve; Muchiri, Mucai; Ngugi, CharlesThe authors review the current state of the science with respect to remote sensing applications for aquaculture, including site location, aquaculture facility mapping, market proximity analysis and associated roadway infrastructure, epizootic mitigation, meteorological event and flood early warning, environmental pollution monitoring, and aquatic ecosystem impact, primarily for catfish (Clarias spp.) and tilapia (Tilapia spp.; Oreochromis spp.), inter alia. The potential of technology transfer from the controlled environment aquaculture research facilities at Purdue University, West Lafayette, Indiana, USA to partnering institutions in Ghana and Kenya are explored. The potential for multi-sensor remote sensing deployment to support sustainable fish production in these environments and subsequently in other African countries is evaluated.Item Influences of land use/cover on water quality in the upper and middle reaches of River Njoro, Kenya(Lakes & Reservoirs: Research and management, 2007-06) Shivoga, William, A.; Muchiri, Mucai; Kibichi, Samuel; Odanga, Jethro; Miller, Scott, N.; Baldyga, Tracy, J.; Enanga, Eric, M.; Gichaba, Maina, C.Data from 10 sampling sites along the River Njoro are used to examine the contribution of nutrients from upstream land uses draining each of the sampling sites. The data also are used to assess whether both the proportion of land uses and the size of the subwatersheds account for the variability in water quality in the River Njoro watershed. Geographical Information System analysis was used to determine the spatial distribution of land-cover types and subwatersheds contributing run-off to the sampling sites in the River Njoro. Standard Digital Elevation Model-based routines were used to establish the watershed area contributing run-off to each sampling site. Water and sediment samples were collected for chemical analysis, and the nutrient levels were related to the upstream land-use types and the size of the subwatersheds. The mid-stream portion of the River Njoro (near Egerton University) accounts for the highest nutrient contributions. The percentage contribution is magnified by additions from industrial, human settlements and agricultural land uses around the University. There is a significant decrease in nutrient levels downstream, however, indicating natural purification as the river flows through an area of large-scale farming with intense, well-preserved riparian and in-stream vegetation. Steep slopes of the land upstream of Egerton University enhance erosion and nutrient losses from those subwatersheds. Mixed small-scale agricultural and bare lands contribute over 55% of the phosphorus load to the upper and mid-reaches of the River Njoro. The size of the subwatershed accounts for about 53% of the variability in the soluble phosphorus in the river. The land-use subwatershed proportions are important for characterizing and modelling water quality in the River Njoro watershed. Upland land uses are as important as near-stream land uses. We suggest that conservation of intact riparian corridor along the river and its tributaries contributes significantly to natural purification processes and recovery of the ecological integrity of the River Njoro ecosystem.Item Ecology and Management of Lake Naivasha, Kenya, in Relation to Climatic Change, Alien Species' Introductions, and Agricultural Development(Environmental Conservation; Cambridge Journals, 1990) Harper, David, M.; Muchiri, Mucai; Mavuti, Kenneth, M.Lake Naivasha is an important freshwater resource for Kenya's foreign-currency-earning agriculture and tourism, and for water-supply. It has always experienced extensive water-level fluctuations as a consequence of irregular rainfall patterns that are affected by continental-scale climatic events, and its communities — particularly of aquatic plants — were adapted to these changes.